Using ANSI SQL Versus Transact SQL

From a performance perspective, it makes little difference. The SQL Server query optimizer will translate from your syntax into the most efficient execution plan. From a coding perspective, it may make a difference if you plan to move code across different types of databases. For example, if you want to write SQL to run in Microsoft Access, then run the same SQL in Microsoft SQL Server, it makes sense to use ANSI SQL rather than Transact SQL.